Electrical water heater



May 29, 1928.

' A. J. KERCHER ET AL.

ELECTRI CAL WATER HEATER May 29, 1928.

A. J. KERCHER- ST AL ELECTRICAL WATER HEATER ,2 ab e h M t 6 0 h S. 2 E n Filed Deo. 17, 192,5

:E 'IIE E INVENTORS ARTHUR J.' KERCHER 30 at least one end '35 both ends of Patented May 29, 1928.

K UNITED srATEs PATENT orFicl-z.

.ARTHUR J'. KERCHER, 0F BERKELEY, AND WILLIAM WESLEY HICKS, OF SAN FRANCISCO, CALIFORNIA.

ELECTRICAL WATER HEATER.

Application led December 17, 1925. Serial No. 75,988.

This invention relates generally to an electrical heat-ing device for .heating fluids n\ and particularly to a heating device to be applied to a hot water tank. It is an object 5 of this invention to devise a heater of this kind which will be inexpensive to manufacture, will have high electrical efliciency and will give long service.

It is a further object of this invention to 10 devise an electrical fluid heater which will have substantially no thermal storage and a very small heat lag, that is, a heater in which the fluid will bev heated within a.

short time after the circuit is closed to en- 5 ergize the resistance conductors.

It is a further object of this invention .to construct an electrical fluid heater in which all of the heating elements are mounted upon a single header so that it may readily be applied to a shell through which the fluid to be heated is adapted to circulate 'and which'will occupy a minimum of space. I v `It is a further object of this invention to devise -a uid heater in which the several heating elements are inthe form of an elongated casing which is so shaped as toA pro- `vide a plurality of .longitudinal passageways connected by a lateral passageway at thereof, and to arrange an insulated resistance conductor within the passageways. It is proposed to shapethe casing by creasing the same longitudinally and toterminate the crease short ofA one or the casing to provide the lateral passageway.l

It is a further object of this invention to devise a luidheaterlin which the separate heating elements are in the form of an elon- 0 gated casing having a plurality of longitudinal passageways and lan `interconnecting lateral passageway, and to provide a resistance conductor within the passageways which is insulated from the casing by re- 45 'fractory insulators threaded over the con- 'l ductor.

It is a further object' of this invention to providea heating unit in which means is. provided ,intermediate the ends of the infj closing casing for engaging the resistance conl uctorl so that sagging. of the conductor will'be prevented when the casing is arranged in an upright position.

Further objects of the invention will appear from the following description in which the preferred embodiments of the invention have been set forth.

Referring to the drawings:

Figure 1 is a transverse sectional view showing an electrical water heater embodying the electrical heating device of this invention.

Fig. 2 is an enlarged section in detail of the invention.

Fig. 3 1s a transverse sectional view taken along lineB-S of Fig. 2.

Fig. 4 is a detail of one form of insulating member for engaging the resistance conductor to prevent sagging of .the same.

Fig. 5 is a detail view of another form of insulating member for engaging a resistance conductor.

Fig. 6 is a transverse sectional view show ing a modified form of the inclosing casing.

Fig. 7 is a transverse sectional view showinganother modification of the inclosing casing. l

Fig. 8 is a transverse sectional view s'howing a third modification of the inclosing casing.

While the heating device of this invention may be employed to heat fluids of any kind, either gases or liquids, it is especially adapted for use as a hot water heater as shown in Fig. 1. Such water heaters usu ally comprise a water tank 10 having connected thereto. a cold water supply pipe 11 which discharges adjacent the lower ortion of the tank 10. The output pipe 12 t rough which the hot water is withdrawn communicates with the tank adjacent its upper end. An external thermal circulating system is provided for heating the water within the tank 10. Thus the water in the lower portion of the tank circulates through the pipes 13 and 14, through the shell-.15 and through the pipes 16 and 17 to be returned again to the upper portion of the tank. within the shell there is an electrical heating device designated generally as 18 for heating the water as it passes through this shell. f

This heating device comprises generally a plurality of heating elements 20 which to secure the heating elements 20 to header Positioned ico 21 in such a manner that they are entirelyy y supportd by the same sc that the entire def' vice may be removed as a unit from the heater. The header 21 is suitably secured to the lower end of the casing as by means of screws or bolts 22 which clamp together the annular flanges 23 and 24 provided upon the header 21 and shell 15 respectively. A gasket 25 is inserted between the opposed faces of these flanges 23 and 24 to secure a water-tight fit.

The heating elements 20 are preferably s constructed of a single elongated casing 27 suitably mounted at its one end in the upper plate 28 of the Aheader 21 and closed at its upperend by means ofa closure plate 29.

' The central portion 28 of the header is suit.

' secured to the upper end of the'casingas by means of brazing, soldering or welding. Both the casing 27 and the closure member 29 are preferably constructed of some metal which has high vheat conduct-ivity such as copper or brass. e

In order to provide. for the positioning of resistance elements within the casing the casing is preferably creased longitudinally to provide a-plurality of longitudinal passageways. Thus, as shown in Fig. 3, the casing isl provided with two opposed longitudinal creases or indentations 31 and 32 whichprovide a plurality of longitudinal passageways 33 and 34. In the particular form of casing shown in Fig. 3 the casing may'be termed a duplex tube since two parallel tubular lpassageways are formed. It is of course obvious that the two lopposed faces of the creased portions 31 and 32 maveither4 bein contact to entirely separate the two i passageways 33 or 34 ormay be spaced from in communication.`

each other so that the two passageways are Instead of extending the creased portions 31 and 32 the entire length. of the casing 21 they are preferably terminated short of the upper end vso that the upper portion 35 of the casing is shaped -1 to provide a lateral passa eway 36, which interconnects the two longitudinal pas geways 33 and 34. Thus, the contour o the upper portion 35 of the casing will' be substantially an oval.Y i

Positioned Vwithin the two longitudinal passageways 33 and 34 are the'resistance conductors 37 and 38 which are preferably convoluted. In order to insulate the resistance conductors fromthe inner walls ofthe casing 27 theyL are provided with 'al series ofcontiguous refractoryinsulating tubes 39 which are threaded upon the conductors.

These insulating tubes are constructed so as Y conducted from the resistance conductors to the water in contact with the casing 27, will be reduced to a minimum.

The resistance conductors 37 and 38 are connected together at their upper ends by an interconnecting conductor 41 which is Y the convoluted resistance conductors 37 and4 38 to sag intermediate their ends, thus Ymaking it possible for the adjacent convolutions to become short-circuited. To prevent this possibility means is provided for supporting the resistance conductors@intermediate the ends of the casing. For this purpose certain of the insulating members 45 are provided with means for engaging the con-v a voluted resistance conductorsv so' as to prevent relative displacement longitudinally with respect to the casing 27. One form of engaging means is shown vin Fig. 4, in which the intermediate insulating member 45 is split to provide two portions 46 and 47 having inner threads 48 adapted to engage the helical convolutions of the resistance conductor. This engagement will effectively prevent relative longitudinal dis- 1 placement between the resistance conductor and the insulating member 45 and since the 3 insulating members 39 are in contiguous relationship with each other and with the 1n.n .termediate member 45 therefore this memberl will also be maintained stationary with re- Ilo spect to the casing 27. vAnother form of env gaging means is shown in'Fig. 5, in which .one of the portions 4S of the split insulating member 45 is provided with inwardly eX- tending gages e the resistance conductor. y

Instead of creasing the casing 27 so as to form two longitudinal passageways it projections 49, each of 'which en# tween two adjacent convolutions of'.

lzo

maybe creased in such a manner as to form i three or more such passageways. shown in F 1g. 6, the casing '627 is c reased Thus, as

longitudinallyat three points along one side 'thereof as at 51, 52 and 53 and is similarlyY creased atfopposed points 54, 55 and 56 along its opposite side: This construction provides four longitudinal passageways 57, 58, 59 and 60 to provide means for positioning the resistance elements 638. Another form of casing is shown in Fig. 7, in which the casing is creased longitudinally only upon one side thereof as at the points 58, 59 and 60 while the side 61 is left plain. A further modiication is shown in Fig. 8, in'. which the casing is creased longitudinally along four sides so as to provide four longitudinal pas,- sageways which are spaced equally about a common center. Thus, the casing 827 is creased as at spaced points 62, 63, 64 and 65 to provide fourlongitudinal passageways 66, 67, 68 and 69, spaced equally about a common center. Within the passageways are disposed the resistance elements 838.

Any suitable means may be provided for connecting together the terminals of the heating elements 20 on the outer side of the header 21. However, it is preferable to provide a plurality of terminal connectors 71 and 72 which are suitably mounted upon an insulating block 73. The insulating block 73 is suitably mounted on the outer side of the header 21 in a recess 74, as by :means Pminal connectors 71 and 72 in any desired housing 78 having its upper rim 79 detachably secured to a depending iange 80 ex- We claimt: o

1. A heating element comprlsln an elongated casing shaped to provide a p urality of ongitudinal passageways and a transverse passageway at one end thereof, electrical resistance means disposed w1th1n` sa1d lpasj sageways, a plurality of refractory insula- \sa1'ne from the inner walls of the casing,

tors strungnpon said means to insulate the means extending from one end pf said casing. 2. A heatingelementcomprising an elongated casing havin a long1tud'inally"ex` tendin indentation 1n at least one side wall;

thereo to provide` a plurality of passages,

- said indentation terminating short of one` end of the casing 'to rovide a lateral passageway, electrical resistance means disposed l'said passageways and a plurality of reand, 'electrical terminal wires" for said resistance sistance means to insulate the .same from the inner walls ofthe casing.

3. In a device' of the class described, an. elongated heat transmitting'casing arranged to extend upwardly, a convoluted resistance conductor disposed Within said casing, a plurality of refractory insulators threaded upon said conductor to insulate the same from the in ner walls of the casing, and

. C of the same in a .direction longitudinal of the casing.

4. In a device of the class described, a casing, a resistance conductor disposed Within the casing, a split refractory insulator through which said conductor is adapted to extend, and means on the insulator engaging the conductor to prevent relative movement between the insulator and conductor.

5. In a device of the class described, an elongated casing. for transmittin heat, a resistance conductor disposed wlthin the casing,'a plurality of4 contiguous refractory insulators through which said conductor is adapted to extend, and means .on at least p 6. In a device of the class described, an elongated casing for transmitting heat, a convoluted resistance conductor disposed Within the casing, a plurality of refractory insulators Y through adapted to extend, and means on atleast one of said insulators for engaging the convolutions of the conductor to the vconductor in a direction longitudinal of thecasing.

7. An electrical heating element comprising a tube like sheet metal s heath indentedV sageways,

integral end portion defining a lateral passageway connecting the longitudinal passageWayS. and an insulated resistance conductor disposed within said longitudinal `passageways and interconnected thru said' lateral passageway.. i

which .said conductor isv prevent sagging of 8. In an electrlcal heating device, an elongated heat transmitting plurality vof refractoryinsulator's threa [upon said conductor tof'insulate the same from the-walls ofthe casing',saidinsulators serving 'to transmit heat lto the?casing, and .means engagingy the conductor intermediate the ends of said casin 'fori' preventing sag Y ging of the samein a irection longitudinal of/the conductor. 's

In testimony whereof, we havehereunto set our hands.

ARTHUR. J. KERCHER.

WESLEY HICKS.

casing, a resistanceA conductor arranged within/said caslng'a. 

